Pull printk updates from Petr Mladek:
- Add a console_msg_format command line option:
The value "default" keeps the old "[time stamp] text\n" format. The
value "syslog" allows to see the syslog-like "<log
level>[timestamp] text" format.
This feature was requested by people doing regression tests, for
example, 0day robot. They want to have both filtered and full logs
at hands.
- Reduce the risk of softlockup:
Pass the console owner in a busy loop.
This is a new approach to the old problem. It was first proposed by
Steven Rostedt on Kernel Summit 2017. It marks a context in which
the console_lock owner calls console drivers and could not sleep.
On the other side, printk() callers could detect this state and use
a busy wait instead of a simple console_trylock(). Finally, the
console_lock owner checks if there is a busy waiter at the end of
the special context and eventually passes the console_lock to the
waiter.
The hand-off works surprisingly well and helps in many situations.
Well, there is still a possibility of the softlockup, for example,
when the flood of messages stops and the last owner still has too
much to flush.
There is increasing number of people having problems with
printk-related softlockups. We might eventually need to get better
solution. Anyway, this looks like a good start and promising
direction.
- Do not allow to schedule in console_unlock() called from printk():
This reverts an older controversial commit. The reschedule helped
to avoid softlockups. But it also slowed down the console output.
This patch is obsoleted by the new console waiter logic described
above. In fact, the reschedule made the hand-off less effective.
- Deprecate "%pf" and "%pF" format specifier:
It was needed on ia64, ppc64 and parisc64 to dereference function
descriptors and show the real function address. It is done
transparently by "%ps" and "pS" format specifier now.
Sergey Senozhatsky found that all the function descriptors were in
a special elf section and could be easily detected.
- Remove printk_symbol() API:
It has been obsoleted by "%pS" format specifier, and this change
helped to remove few continuous lines and a less intuitive old API.
- Remove redundant memsets:
Sergey removed unnecessary memset when processing printk.devkmsg
command line option.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (27 commits)
printk: drop redundant devkmsg_log_str memsets
printk: Never set console_may_schedule in console_trylock()
printk: Hide console waiter logic into helpers
printk: Add console owner and waiter logic to load balance console writes
kallsyms: remove print_symbol() function
checkpatch: add pF/pf deprecation warning
symbol lookup: introduce dereference_symbol_descriptor()
parisc64: Add .opd based function descriptor dereference
powerpc64: Add .opd based function descriptor dereference
ia64: Add .opd based function descriptor dereference
sections: split dereference_function_descriptor()
openrisc: Fix conflicting types for _exext and _stext
lib: do not use print_symbol()
irq debug: do not use print_symbol()
sysfs: do not use print_symbol()
drivers: do not use print_symbol()
x86: do not use print_symbol()
unicore32: do not use print_symbol()
sh: do not use print_symbol()
mn10300: do not use print_symbol()
...
Pull RCU updates from Paul E. McKenney:
- Updates to use cond_resched() instead of cond_resched_rcu_qs()
where feasible (currently everywhere except in kernel/rcu and
in kernel/torture.c). Also a couple of fixes to avoid sending
IPIs to offline CPUs.
- Updates to simplify RCU's dyntick-idle handling.
- Updates to remove almost all uses of smp_read_barrier_depends()
and read_barrier_depends().
- Miscellaneous fixes.
- Torture-test updates.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that both smp_read_barrier_depends() and read_barrier_depends()
are being de-emphasized, warn if any are added.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
[ paulmck: Skipped checking files and handled whitespace per Joe Perches. ]
printk specifier %p now hashes all addresses before printing. Sometimes
we need to see the actual unmodified address. This can be achieved using
%lx but then we face the risk that if in future we want to change the
way the Kernel handles printing of pointers we will have to grep through
the already existent 50 000 %lx call sites. Let's add specifier %px as a
clear, opt-in, way to print a pointer and maintain some level of
isolation from all the other hex integer output within the Kernel.
Add printk specifier %px to print the actual unmodified address.
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Currently running checkpatch on a directory with a cover-letter.patch
file reports the following error:
-----------------------------------------
patches/smp-v2/v2-0000-cover-letter.patch
-----------------------------------------
ERROR: Does not appear to be a unified-diff format patch
The logic to suppress the unified-diff check for cover letters is there
but is checking $file instead of $filename. Fix the variable to use the
correct one.
Link: http://lkml.kernel.org/r/20170909090406.31523-1-shorne@gmail.com
Signed-off-by: Stafford Horne <shorne@gmail.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Unlike all other types, LONG_LINE, LONG_LINE_COMMENT and LONG_LINE_STRING
are passed to WARN() through a variable. This causes the parser in
list_types() to miss them and consequently they are not present in the
output of --list-types.
Additionally, types TYPO_SPELLING, FSF_MAILING_ADDRESS and AVOID_BUG are
passed with a variable level, causing the parser to miss them too.
So modify the regex to also catch these special cases.
Link: http://lkml.kernel.org/r/20170902175610.7e4a7c9d@endymion
Fixes: 3beb42eced ("checkpatch: add --list-types to show message types to show or ignore")
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The boolean --color argument did not offer the ability to force
colourized output even if stdout is not a terminal. Change the format
of the argument to the familiar --color[=WHEN] construct as seen in
common Linux utilities such as git, ls and dmesg, which allows the user
to specify whether to colourize output "always", "never", or "auto" when
the output is a terminal. The default is "auto".
The old command-line uses of --color and --no-color are unchanged.
Link: http://lkml.kernel.org/r/efe43bdbad400f39ba691ae663044462493b0773.1496799721.git.joe@perches.com
Signed-off-by: John Brooks <john@fastquake.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As of perl 5, version 26, subversion 0 (v5.26.0) some new warnings have
occurred when running checkpatch.
Unescaped left brace in regex is deprecated here (and will be fatal in
Perl 5.30), passed through in regex; marked by <-- HERE in m/^(.\s*){
<-- HERE \s*/ at scripts/checkpatch.pl line 3544.
Unescaped left brace in regex is deprecated here (and will be fatal in
Perl 5.30), passed through in regex; marked by <-- HERE in m/^(.\s*){
<-- HERE \s*/ at scripts/checkpatch.pl line 3885.
Unescaped left brace in regex is deprecated here (and will be fatal in
Perl 5.30), passed through in regex; marked by <-- HERE in
m/^(\+.*(?:do|\))){ <-- HERE / at scripts/checkpatch.pl line 4374.
It seems perfectly reasonable to do as the warning suggests and simply
escape the left brace in these three locations.
Link: http://lkml.kernel.org/r/20170607060135.17384-1-cyrilbur@gmail.com
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Acked-by: Joe Perches <joe@perches.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a block that identifies multiple line function definitions.
Save the function name into $context_function to improve the embedded
function name test.
Look for misplaced open brace on the function definition.
Emit an OPEN_BRACE error when the function definition is similar to
void foo(int arg1,
int arg2) {
Miscellanea:
o Remove the $realfile test in function declaration w/o named arguments test
o Comment the function declaration w/o named arguments test
Link: http://lkml.kernel.org/r/de620ed6ebab75fdfa323741ada2134a0f545892.1496835238.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: David Kershner <david.kershner@unisys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
